Efficacy of isoproturon and pendimethalin against resistant biotypes of Rumex spp. in wheat (Triticum aestivum L.)

Persistence of weeds under irrigation conditions is inevitable and manual management practices are labour intensive and cumbersome. As far as wheat is concerned huge losses in yield, are incurred due to Rumex spp. Therefore, the present study was carried out to evaluate the efficacy of herbicides against Rumex spp. during the Rabi, 2017–18 at Department of Agronomy, Chaudhary Charan Singh Haryana Agricultural University, Hisar (Haryana). Isoproturon as post- emergence and pendimethalin as pre-emergence were taken as treatments and applied at three doses (0.5X, 1.0X and 2.0X) under pot study ‘X’ is the recommended dose of herbicide@ 1000g/ha for isoproturon and 1500g/ha for pendimethalin.Four populations of Rumex spp. named as HHH (HAU Hisar), UPH (Ujha, Panipat), JHH (Jind) and JJR (Jhajjar) collected from putative resistance affected farmer's field.UPH and JHH populations are highly resistant whereas JJR population is moderately resistant to sulphonylureas herbicides. HHH population is sensitive so used as standard check for comparison. Majority of biotypes showed sensitivity against isoproturon at recommended dose except UPH biotype. It provided 70–90 per cent control to all biotypes at double of recommended doses. Lower values of plant height, chlorophyll fluorescence, fresh and dry weight were observed in isoproturon treated plants. Rumex biotypes were highly sensitive to pendimethalin when applied as pre emergence. It provided complete control to all biotypes. The information collected from this study will facilitate proactive management of Rumex spp. through sequential application of pre and post emergence herbicides.